Merge pull request #1698 from ivanpenaloza/july13

adding updates

Author: ivanpenaloza

src/my_project/interviews/google_top_exercises/round_1/17_maximum_binary_tree.py

@@ -0,0 +1,16 @@
+from typing import Optional
+
+class TreeNode:
+    def __init__(self, val=0, left=None, right=None):
+        self.val = val
+        self.left = left
+        self.right = right
+
+
+class Solution:
+    def maxDepth(self, root: Optional[TreeNode]) -> int:
+
+        if not root: 
+            return 0
+        else: 
+            return max(self.maxDepth(root.left), self.maxDepth(root.right)) + 1